The growth mechanism of copper films coated on cenosphere particles using magnetron sputtering method

Abstract

The characteristics of copper film coated on cenosphere particles using the magnetron sputtering method were investigated by field emission scanning electron microscopy (FE-SEM), x-ray diffraction (XRD), field emission transmission electron microscopy (TEM) and atomic force microscopy (AFM). The FE-SEM and AFM results show that the grain sizes and root-mean-square roughness values of the copper films increase with the increase in sputtering power or deposition time and the growth of the copper films is a three-dimensional island growth mode. The angular distribution (angle of incidence) and adatom mobility are the two important factors that influence the film growth processes and the film properties. A new film growth model, which is called the variational angle distribution growth model, is proposed to explain the growth mechanism of the copper film coated on cenosphere particles in the paper. The unceasingly variational angular distribution can get rid of the physical shadowing effect of the sputtering deposition and promote a rather smooth film growth. Deposition with high adatom mobility materials creates larger diameter islands than deposition with low adatom mobility ones. Due to the all-round effect, the final distribution of grains shows a rather smooth morphology with low roughness. The XRD results show that the copper film coated on cenospheres is a face centred cubic (fcc) structure and the crystallization of the film sample increases with increasing sputtering power or sputtering time. The high resolution transmission electron microscopy result shows the nano-crystalline copper film with different crystal orientations uniformly coated on amorphous cenosphere particles.